Optimal discrete model reduction by multipoint Padé approximation

A discrete-time multipoint Padé approximation method is presented that derives optimal reduced-order models. The method is seen to be easily implemented using a recently developed way of calculating Padé approximants. An important result that relates the optimal model to multipoint Padé approximation is proved and the whole process isseen to consist of multiplying matrices and solving linear equations. Numerical examples are given to illustrate the application of the new method.